CN115958471A - Photomask substrate processing method - Google Patents
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- CN115958471A CN115958471A CN202211700720.XA CN202211700720A CN115958471A CN 115958471 A CN115958471 A CN 115958471A CN 202211700720 A CN202211700720 A CN 202211700720A CN 115958471 A CN115958471 A CN 115958471A
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Abstract
The invention discloses a processing method of a photomask substrate, wherein the photomask substrate is made of a glass substrate, and the processing method comprises the following steps: performing edge grinding, chamfering and spray cleaning on the glass substrate to obtain measurement data for processing the glass substrate, determining a processing scheme according to the measurement data, and sequentially performing grinding with different precisions by using diamond grinding wheels with different precisions; the method comprises the steps of carrying out rough polishing and fine polishing on a glass substrate in sequence by using polishing equipment after grinding, carrying out grinding with different accuracies in sequence by using diamond grinding wheels with different accuracies, gradually removing a damaged layer on the surface of the glass substrate after the previous grinding while quickly improving the flatness of raw materials, continuously feeding the diamond grinding wheels along a Y axis when the raw materials reciprocate along the X axis, obtaining a uniform frosted surface without feed marks and steps after grinding, and having low requirements on the raw materials, simple and convenient process flow, high processing efficiency, low production cost and high economic utility.
Description
Technical Field
The present disclosure relates to photomask blanks, and particularly to a method for processing a photomask blank.
Background
The mask plate is also called as a photomask, is a pattern transfer master plate in the microelectronic manufacturing process, and is widely applied to the fields of semiconductors, flat panel displays, printed circuit boards and the like. The mask plate has the function similar to that of the negative film of a traditional camera, and has the function of transferring a designed circuit pattern to a photoresist film on a wafer or a quartz substrate through the working procedures of photoetching, developing, etching and the like under the coordination of a photoetching machine and photoresist so as to copy the circuit pattern, thereby realizing batch production.
According to different downstream application industries, the mask can be divided into a panel mask, a semiconductor mask, a touch control mask and a circuit board mask. The panel mask can be used in the fields of thin film transistor liquid crystal display (TFT-LCD), active Matrix Organic Light Emitting Diode (AMOLED), fine Metal Masks (FMM) and the like. The panel mask evolves towards both large size and high precision. On the one hand, the screen size of consumer electronics products such as flat panel televisions, smart phones and computers is increasing, the development of the global flat panel display industry is large in size, the size of the mask is correspondingly large, and higher challenges are provided for the manufacturing of the mask. On the other hand, in order to meet the increasing demands of consumers on display products, flat panel displays are being developed toward higher definition and higher color saturation. Research institutes predict that the display accuracy of future display screens will be gradually improved from 450PPI (pixels per inch) to over 650 PPI. The continuous improvement of the number of pixels per inch can also bring the improvement of the requirements on parameters such as the photoetching resolution, the CD uniformity, the defect size, the alignment precision and the like of the flat panel display mask.
The most important raw material in the mask is a mask substrate, and the mask substrate is used as a carrier of a mask pattern and plays an important role in the precision and quality of a mask product. The substrate must have good optical transmission characteristics, dimensional and chemical stability, flatness, and the like, and have no micro defects such as sand inclusion and bubbles. Quartz glass has become a mainstream material for making masks in recent years due to its stable chemical properties, high optical transmittance and low thermal expansion coefficient. For large-sized mask substrates, surface flatness and micro-defects are critical factors determining their accuracy. If the flatness of the large-sized mask substrate is low, when the light is directly emitted, the light is deflected, the size of the photoetching pattern is changed (enlarged or reduced) and the photoetching resolution is reduced compared with an ideal plane. Therefore, it is a basic premise to secure high flatness of the mask substrate and to obtain high accuracy.
The existing flatness processing method of the large-size photomask substrate is realized by at least one of grinding, grinding and polishing. The main purpose is to obtain a photomask substrate with high flatness so as to improve the photoetching resolution.
The invention patent CN 1437045A-large size substrate and its manufacturing method, discloses a large size substrate, which has a diagonal length not less than 500mm and a flatness/diagonal length ratio not more than 6.0 x 10-6. The method comprises the steps of firstly carrying out double-sided grinding processing on a raw material plate, and enabling the parallelism to reach 50um or even below 10um in advance, otherwise, removing a thicker part of the plate through subsequent processing, so that the processing time is long, and the removal thickness of the plate is too much. And then, locally processing the high points on the surface of the plate by controlling the processing parameters of the sand blaster. The method has high requirements on the parallelism of raw materials, the sand blasting process is complex, and the method has high requirements on operators and processing equipment, so that the application is limited to a certain extent.
Patent CN 101246312-recycling of large-size photomask substrates, discloses a method of recycling used large-size photomask substrates having a patterned light-shielding film. The method uses a sand blasting + polishing process to prepare the reusable photomask substrate. However, this method requires a thickness of at least 3mm for the raw material, and also performs surface reconditioning of the glass substrate by a complicated sand blasting process.
Patent CN 101804589A-a method for processing an artificial quartz glass substrate for semiconductors, which discloses a method for processing an artificial quartz glass substrate for semiconductors using a small rotary polishing member. The method requires that the surface flatness of the substrate to be polished should be at least 2um to allow polishing. Also, when the area of the glass substrate to be processed is larger than 1 × 105mm2 (about 223.6mm in diagonal), since the contact area of the small rotary tool is too small with respect to the substrate, the processing time may be very long.
Disclosure of Invention
In view of the existing photomask substrate processing method, when the size of a photomask substrate is larger, the method has higher limitation on the thickness, the planeness, the parallelism and the like of raw materials, the process flow is relatively complex, the processing time is long, and the economic utility is lower.
In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:
a photomask substrate processing method, wherein the photomask substrate raw material is a glass substrate, and the processing method comprises the following steps:
carrying out primary treatment on the glass substrate;
carrying out spray cleaning on the glass substrate;
obtaining measurement data for processing the glass substrate, and determining a processing scheme according to the measurement data;
the glass substrate is processed according to a processing recipe.
According to one aspect of the present invention, the edging, chamfering and chamfering of the glass substrate comprises: and (3) flatly placing the glass substrate on a rubber vacuum chuck of a carving machine, and performing edge grinding, edge grinding and chamfering processing.
In accordance with one aspect of the present invention, the spray cleaning of the glass substrate comprises: the glass substrate is placed in a water tank, the front side and the back side of the glass substrate are cleaned in a spraying mode, and after the glass substrate is cleaned in the spraying mode, water marks on the front side and the back side of the glass substrate are dried through clean compressed air.
According to an aspect of the present invention, the measuring glass substrate basic data includes: the flatness, parallelism, thickness and surface shape of the glass substrate were measured using a flatness image tester, and the total feed amount of the grinding process was calculated from the surface shape of the glass substrate.
In accordance with one aspect of the invention, the processing scheme comprises:
selecting a surface with poor flatness as a front surface, wherein the other surface is a back surface, and the front surface is a first processed surface;
grinding the glass substrate;
and polishing the glass substrate.
According to an aspect of the present invention, the grinding of the glass substrate includes: the method comprises the steps of flatly placing a glass substrate on a magnetic suction working table surface of a surface grinding machine, using precision clearance rules with different thicknesses, measuring a proximity clearance between a raw material glass substrate and the working table surface, filling an adjusting clearance through the precision clearance rules with proper thickness, selecting diamond grinding wheels with different particle sizes to sequentially perform rough grinding, semi-fine grinding and fine grinding on the glass substrate, and spraying and cleaning the glass substrate after grinding each time.
In accordance with one aspect of the invention, the method of rough grinding comprises: the method comprises the following steps of carrying out rough grinding by using a diamond grinding wheel with the particle size of 270#, carrying out reciprocating motion on a glass substrate along the X-axis direction, continuously feeding the diamond grinding wheel along the Y-axis direction, carrying out reciprocating motion once along the Y-axis direction, then intermittently feeding the diamond grinding wheel along the Z-axis direction to be vertical to the front surface of the glass substrate once again, carrying out rough grinding and spray cleaning on the back surface of the glass substrate after rough grinding and spray cleaning are carried out on the front surface of the glass substrate, and measuring the surface flatness of the ground glass substrate.
In accordance with one aspect of the present invention, the method of semi-finish grinding comprises: and carrying out semi-fine grinding by using a diamond grinding wheel with the grain diameter of 500#, carrying out reciprocating motion on the glass substrate along the X-axis direction, continuously feeding the diamond grinding wheel along the Y-axis direction, carrying out intermittent feeding once again on the diamond grinding wheel along the Z-axis direction and perpendicular to the front surface of the glass substrate after carrying out reciprocating motion once along the Y-axis direction, carrying out semi-fine grinding and spray cleaning on the back surface of the glass substrate after carrying out semi-fine grinding and spray cleaning on the front surface of the glass substrate, and measuring the surface flatness of the ground glass substrate.
According to an aspect of the invention, the method of fine grinding comprises: the method comprises the steps of performing fine grinding by using a diamond grinding wheel with the grain size of 800# -1340#, enabling a glass substrate to reciprocate along the X-axis direction, feeding the diamond grinding wheel continuously along the Y-axis direction, enabling the diamond grinding wheel to feed the diamond grinding wheel intermittently again along the Z-axis direction and perpendicular to the front surface of the glass substrate after the diamond grinding wheel reciprocates once, performing fine grinding and spray cleaning on the back surface of the glass substrate after the front surface of the glass substrate is subjected to fine grinding and spray cleaning, and measuring the flatness of the surface of the ground glass substrate.
According to an aspect of the present invention, the polishing process of the glass substrate includes: carrying out rough polishing and fine polishing on the glass substrate in sequence; the rough polishing comprises the following steps: after grinding, polishing the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 1-5 um; the fine polishing comprises the following steps: and after grinding, carrying out chemical mechanical polishing on the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into the star plate, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 0.5-3 um.
The implementation of the invention has the advantages that: the invention provides a processing method of a photomask substrate, wherein the photomask substrate is made of a glass substrate as a raw material, and the processing method comprises the following steps: performing edge grinding, chamfering and spray cleaning on the glass substrate to obtain measurement data for processing the glass substrate, determining a processing scheme according to the measurement data, and sequentially performing grinding with different precisions by using diamond grinding wheels with different precisions; the method comprises the steps of carrying out rough polishing and fine polishing on a glass substrate in sequence by using polishing equipment after grinding, carrying out grinding with different accuracies in sequence by using diamond grinding wheels with different accuracies, gradually removing a damaged layer on the surface of the glass substrate after the previous grinding while quickly improving the flatness of raw materials, continuously feeding the diamond grinding wheels along a Y axis when the raw materials reciprocate along the X axis, obtaining a uniform frosted surface without feed marks and steps after grinding, and having low requirements on the raw materials, simple and convenient process flow, high processing efficiency, low production cost and high economic utility.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a flow chart of a method for processing a photomask substrate according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Example 1
As shown in fig. 1, a method for processing a photomask substrate, the photomask substrate being a synthetic quartz glass substrate having a size of 450 × 550mm (a diagonal length of 711 mm) and a thickness of 5.0mm, the method comprising:
s1, performing primary treatment on a glass substrate;
horizontally placing the glass substrate on a rubber vacuum chuck of a carving machine, and performing edge grinding, edge grinding and chamfering processing;
s2, carrying out spray cleaning on the glass substrate;
the glass substrate is placed in a water tank, the front side and the back side of the glass substrate are cleaned in a spraying mode, and after the glass substrate is cleaned in the spraying mode, water marks on the front side and the back side of the glass substrate are dried through clean compressed air.
And step S3: obtaining measurement data for processing the glass substrate, and determining a processing scheme according to the measurement data;
the flatness image tester is used for measuring the flatness, parallelism, thickness and surface shape of the glass substrate, and the total feed amount of the rough grinding process is calculated.
The processing scheme comprises the following steps:
selecting a surface with poor flatness as a front surface, wherein the other surface is a back surface, and the front surface is a first processed surface;
grinding the glass substrate;
and polishing the glass substrate.
In this embodiment, the original glass substrate has a plane a of 28um, a B of 46um, a parallelism of 15um, and a thickness of 5.062mm, the B with poor flatness is used as the front surface, and the surface is convex, i.e., the middle area is high, and the four side areas are low.
In practical application, flatness, parallelism and thickness are measured, a group of high-precision KEYENCE laser transmitters are adopted to emit visible red laser to the surface of a measured object, the laser reflected by the object is received by an internal CCD linear camera through a receiver lens, the CCD linear camera can receive light spots at different angles according to different distances, and based on the light spots, a digital signal processor can calculate the thickness of the glass substrate to be measured, meanwhile, surface point cloud data of the glass substrate to be measured are obtained, and then the flatness and the parallelism of the glass substrate to be measured are obtained through a software algorithm.
S4, processing the glass substrate according to the processing scheme;
keep flat the glass substrate on flat grinder's magnetism is inhaled table surface, uses the accurate clearance chi of 10um, 20um, 50um thickness, measures the clearance that closes on between raw and other materials glass substrate and the table surface, fills the adjustment clearance through the accurate clearance chi of suitable thickness.
The grinding process of the glass substrate includes: and selecting diamond grinding wheels with different grain diameters to carry out rough grinding, semi-fine grinding and fine grinding on the glass substrate in sequence, and spraying and cleaning the glass substrate after grinding each time.
The polishing process of the glass substrate includes: and performing rough polishing and fine polishing on the glass substrate in sequence.
In practical application, when the gap is larger, a precision gap ruler with proper thickness can be used for filling the gap between the glass substrate and the worktable.
Step S41, carrying out coarse grinding processing on the glass substrate;
carrying out rough grinding by using a diamond grinding wheel with the particle size of 270#, continuously feeding the diamond grinding wheel of 270#, after the diamond grinding wheel reciprocates once along the Y-axis direction at the speed of 300mm/min, intermittently feeding the diamond grinding wheel of 270#, wherein the diamond grinding wheel is vertical to the front surface of the glass substrate along the Z-axis direction, the single feeding amount is 10um, and the total feeding amount is 50 um.
And turning the glass, grinding the surface A, continuously feeding the 270# diamond grinding wheel along the Y-axis direction at the speed of 300mm/min, and feeding the 270# diamond grinding wheel along the Z-axis direction at a time by 10um, wherein the total feed is 30um. After the grinding procedure is finished, the surface of the glass substrate is washed clean by pure water and then dried by clean compressed air. And measuring the flatness of the surface of the ground glass substrate by adopting a VML7S ultra-precise electronic level meter, and measuring the flatness to be 13.3um.
Step S42: carrying out semi-finish grinding processing on the glass substrate;
and after the grinding procedure is finished, the surface of the glass substrate is washed clean by pure water and dried by clean compressed air, and the surface flatness of the ground glass substrate is measured by a VML7S ultra-precise electronic level meter.
And turning the glass, grinding the surface A, continuously feeding the 500# diamond grinding wheel at a speed of 300mm/min along the Y-axis direction, and continuously feeding the 500# diamond grinding wheel at a single feeding amount of 5um and a total feeding amount of 20um along the Z-axis direction, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Step S43: carrying out fine grinding processing on the glass substrate;
the method comprises the steps of carrying out fine grinding by using a diamond grinding wheel with the particle size of 800#, feeding the diamond grinding wheel of 800# continuously along the Y-axis direction at the speed of 300mm/min, after the diamond grinding wheel reciprocates once along the Y-axis direction, feeding the diamond grinding wheel of 800# intermittently along the Z-axis direction to be vertical to the front surface of a glass substrate once, wherein the feeding amount of each time is 3 mu m, and the total feeding amount is 10 mu m.
And turning the glass, grinding the surface A, continuously feeding the 800# diamond grinding wheel along the Y-axis direction at the speed of 300mm/min, carrying out single feeding of the 800# diamond grinding wheel along the Z-axis direction by 3um and total feeding of 10um, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Carrying out fine grinding by using a diamond grinding wheel with the grain diameter of 1340#, continuously feeding the diamond grinding wheel of 1340# along the Y-axis direction at the speed of 300mm/min, after the diamond grinding wheel reciprocates once along the Y-axis direction, intermittently feeding the diamond grinding wheel of 1340# along the Z-axis direction to be vertical to the front surface of the glass substrate once, wherein the single feeding amount is 1um, and the total feeding amount is 5 um.
And then, turning the glass, grinding the surface A, continuously feeding the 1340# diamond grinding wheel at the speed of 300mm/min along the Y-axis direction, cleaning the surface of the glass substrate by pure water after the grinding procedure is finished, drying the glass substrate by clean compressed air, measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter, and measuring the front surface flatness of the ground glass substrate to be 7.1um and the back surface flatness to be 6.1um.
Step S44: roughly polishing the glass substrate;
after grinding, polishing the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 1-5 um;
step S45: carrying out fine polishing processing on the glass substrate;
the fine polishing comprises the following steps: after grinding, carrying out chemical mechanical polishing on the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the particle size of 0.5-3 um;
after the mechanical polishing is finished, the flatness image tester is adopted to measure the flatness of the glass substrate to be 4.8um and 4.2um.
In practical application, the polishing powder is mainly cerium dioxide, and is suspended in water at a concentration of 5wt% to 15wt%.
Example 2
The photomask substrate raw material is a synthetic quartz glass substrate, the size of which is 420 multiplied by 520mm (the diagonal length is 668 mm), the thickness of which is 5.0mm, and the processing method comprises the following steps:
s1, performing primary treatment on a glass substrate;
horizontally placing the glass substrate on a rubber vacuum chuck of a carving machine, and performing edge grinding, edge grinding and chamfering processing;
s2, carrying out spray cleaning on the glass substrate;
the glass substrate is placed in a water tank, the front side and the back side of the glass substrate are sprayed and cleaned, and after the glass substrate is sprayed and cleaned, water marks on the front side and the back side of the glass substrate are dried by clean compressed air.
And step S3: obtaining measurement data for processing the glass substrate, and determining a processing scheme according to the measurement data;
the flatness, parallelism, thickness and surface shape of the glass substrate were measured by a flatness image tester, and the total feed amount of rough grinding was calculated.
The processing scheme comprises the following steps:
selecting a surface with poor flatness as a front surface, wherein the other surface is a back surface, and the front surface is a first processed surface;
grinding the glass substrate;
and polishing the glass substrate.
In this embodiment, the original glass substrate has a flatness A surface of 52um, a B surface of 32um, a parallelism of 11um and a thickness of 4.821mm, and the A surface with poor flatness is used as the front surface.
S4, processing the glass substrate according to the processing scheme;
keep flat the glass substrate on flat grinder's magnetism is inhaled table surface, uses the accurate clearance chi of 10um, 20um, 50um thickness, measures the clearance that closes on between raw and other materials glass substrate and the table surface, fills the adjustment clearance through the accurate clearance chi of suitable thickness.
The grinding process of the glass substrate includes: and selecting diamond grinding wheels with different grain diameters to carry out rough grinding, semi-fine grinding and fine grinding on the glass substrate in sequence, and spraying and cleaning the glass substrate after grinding each time.
The polishing process of the glass substrate includes: and performing rough polishing and fine polishing on the glass substrate in sequence.
Step S41, carrying out coarse grinding processing on the glass substrate;
carrying out rough grinding by using a diamond grinding wheel with the particle size of 270#, continuously feeding the diamond grinding wheel of 270#, after the diamond grinding wheel reciprocates once along the Y-axis direction at the speed of 300mm/min, intermittently feeding the diamond grinding wheel of 270#, the diamond grinding wheel is perpendicular to the front surface of the glass substrate along the Z-axis direction once, feeding the diamond grinding wheel once at a single time, wherein the feeding amount is 10 microns, and the total feeding amount is 50 microns.
And turning the glass, grinding the surface A, continuously feeding the 270# diamond grinding wheel along the Y-axis direction at a speed of 300mm/min, and feeding the 270# diamond grinding wheel along the Z-axis direction by 10um in a single time, wherein the total feed is 30um. After the grinding process is finished, the surface of the glass substrate is washed clean by pure water and then dried by clean compressed air. And measuring the surface flatness of the ground glass substrate by adopting a VML7S ultra-precise electronic level meter.
Step S42: carrying out semi-finish grinding processing on the glass substrate;
and after the grinding procedure is finished, the surface of the glass substrate is washed clean by pure water and dried by clean compressed air, and the surface flatness of the ground glass substrate is measured by a VML7S ultra-precise electronic level meter.
And turning the glass, grinding the A surface, continuously feeding the 500# diamond grinding wheel at a speed of 300mm/min along the Y-axis direction, performing single feeding of the 500# diamond grinding wheel along the Z-axis direction by 5 micrometers, performing total feeding by 20 micrometers, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Step S43: carrying out fine grinding processing on the glass substrate;
carrying out fine grinding by using a diamond grinding wheel with the grain diameter of 800#, continuously feeding the diamond grinding wheel of 800#, after carrying out reciprocating motion once along the Y-axis direction, intermittently feeding the diamond grinding wheel of 800#, wherein the diamond grinding wheel is vertical to the front surface of the glass substrate along the Z-axis direction, the feeding amount of each time is 3um, and the total feeding amount is 10um.
And turning the glass, grinding the surface A, continuously feeding the 800# diamond grinding wheel along the Y-axis direction at the speed of 300mm/min, carrying out single feeding of the 800# diamond grinding wheel along the Z-axis direction by 3um and total feeding of 10um, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
The method comprises the steps of carrying out fine grinding by using a diamond grinding wheel with the grain size of 1340#, feeding the diamond grinding wheel with the grain size of 1340# continuously along the Y-axis direction at the speed of 300mm/min, after the diamond grinding wheel with the grain size of 1340# reciprocates once, feeding the diamond grinding wheel with the grain size of 1340# intermittently once along the Z-axis direction and perpendicular to the front surface of a glass substrate, wherein the single feeding amount is 1um, and the total feeding amount is 5 um.
And turning the glass, grinding the A surface, continuously feeding the 1340# diamond grinding wheel at the speed of 300mm/min along the Y-axis direction, performing single feeding of the 1340# diamond grinding wheel along the Z-axis direction by 1um, and performing total feeding by 5um, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Step S44: roughly polishing the glass substrate;
the rough polishing comprises the following steps: after grinding, polishing the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 1-5 um;
step S45: carrying out fine polishing processing on the glass substrate;
the fine polishing comprises the following steps: after grinding, carrying out chemical mechanical polishing on the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the particle size of 0.5-3 um;
after the mechanical polishing is finished, a flatness image tester is adopted to measure the flatness of the glass substrate to be 7.4um and 5.8um.
Example 3
The photomask blank material was a synthetic quartz glass substrate having a size of 520X 800mm (954 mm in diagonal length) and a thickness of 9.8mm, and the processing method included:
step 1, carrying out primary treatment on a glass substrate;
horizontally placing the glass substrate on a rubber vacuum chuck of a carving machine, and performing edge grinding, edge grinding and chamfering processing;
s2, carrying out spray cleaning on the glass substrate;
the glass substrate is placed in a water tank, the front side and the back side of the glass substrate are sprayed and cleaned, and after the glass substrate is sprayed and cleaned, water marks on the front side and the back side of the glass substrate are dried by clean compressed air.
And step S3: obtaining measurement data for processing the glass substrate, and determining a processing scheme according to the measurement data;
the flatness, parallelism, thickness and surface shape of the glass substrate were measured by a flatness image tester, and the total feed amount of rough grinding was calculated.
The processing scheme comprises the following steps:
selecting a surface with poor flatness as a front surface, wherein the other surface is a back surface, and the front surface is a first processed surface;
grinding the glass substrate;
and polishing the glass substrate.
In this example, the original glass substrate has a flatness A surface of 89um, a B surface of 63um, a parallelism of 51um, and a thickness of 9.807mm, and the A surface with poor flatness is used as the front surface.
S4, processing the glass substrate according to the processing scheme;
keep flat the glass substrate on flat grinder's magnetism is inhaled table surface, uses the accurate clearance chi of 10um, 20um, 50um thickness, measures the clearance that closes on between raw and other materials glass substrate and the table surface, fills the adjustment clearance through the accurate clearance chi of suitable thickness.
The grinding process of the glass substrate includes: and selecting diamond grinding wheels with different grain diameters to carry out rough grinding, semi-fine grinding and fine grinding on the glass substrate in sequence, and spraying and cleaning the glass substrate after grinding each time.
The polishing process of the glass substrate includes: and performing rough polishing and fine polishing on the glass substrate in sequence. .
Step S41, carrying out coarse grinding processing on the glass substrate;
carrying out rough grinding by using a diamond grinding wheel with the particle size of 270#, continuously feeding the diamond grinding wheel of 270#, after reciprocating motion in the Y-axis direction once, intermittently feeding the diamond grinding wheel of 270#, perpendicular to the front surface of the glass substrate, in the Z-axis direction once, wherein the single feeding amount is 10 microns, and the total feeding amount is 260 microns.
And turning the glass, grinding the surface A, continuously feeding the 270# diamond grinding wheel along the Y-axis direction at the speed of 400mm/min, and feeding the 270# diamond grinding wheel along the Z-axis direction by 10um in a single time, wherein the total feed is 110um. After the grinding process is finished, the surface of the glass substrate is washed clean by pure water and then dried by clean compressed air. And measuring the flatness of the surface of the ground glass substrate by adopting a VML7S ultra-precise electronic level meter, and measuring the flatness to be 13.7um.
Step S42: carrying out semi-fine grinding processing on the glass substrate;
and after the grinding procedure is finished, the surface of the glass substrate is washed clean by pure water and dried by clean compressed air, and the surface flatness of the ground glass substrate is measured by a VML7S ultra-precise electronic level meter.
And turning the glass, grinding the surface A, continuously feeding the 500# diamond grinding wheel at a speed of 400mm/min along the Y-axis direction, carrying out single feeding of the 500# diamond grinding wheel along the Z-axis direction by 5 microns, carrying out total feeding by 30 microns, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Step S43: carrying out fine grinding processing on the glass substrate;
carrying out fine grinding by using a diamond grinding wheel with the grain diameter of 800#, continuously feeding the diamond grinding wheel of 800#, after carrying out reciprocating motion once along the Y-axis direction, intermittently feeding the diamond grinding wheel of 800#, wherein the diamond grinding wheel is vertical to the front surface of the glass substrate along the Z-axis direction, the feeding amount of each time is 3um, and the total feeding amount is 10um.
And turning the glass, grinding the surface A, continuously feeding the 800# diamond grinding wheel along the Y-axis direction at the speed of 400mm/min, performing single feeding of the 800# diamond grinding wheel along the Z-axis direction by 3um, and performing total feeding of 10um, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Carrying out fine grinding by using a diamond grinding wheel with the grain diameter of 1000#, continuously feeding the diamond grinding wheel of 1000# along the Y-axis direction at the speed of 400mm/min, after carrying out reciprocating motion once along the Y-axis direction, intermittently feeding the diamond grinding wheel of 1000# along the Z-axis direction to be vertical to the front surface of the glass substrate once, wherein the single feeding amount is 1um, and the total feeding amount is 5 um.
And turning the glass, grinding the surface A, continuously feeding the 1000# diamond grinding wheel at a speed of 400mm/min along the Y-axis direction, and continuously feeding the 1000# diamond grinding wheel at a single feeding amount of 1um and a total feeding amount of 5um along the Z-axis direction, wherein after the grinding process is finished, the surface of the glass substrate is washed clean by pure water and dried by clean compressed air, and the surface flatness of the ground glass substrate is measured by adopting a VML7S ultra-precise electronic level meter.
Step S44: roughly polishing the glass substrate;
the rough polishing comprises the following steps: after grinding, polishing the raw material glass substrate chemically and mechanically by using polishing equipment, flatly placing the glass substrate into a star plate, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 1-5 mu m;
step S45: carrying out fine polishing processing on the glass substrate;
the fine polishing comprises the following steps: after grinding, carrying out chemical mechanical polishing on the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the particle size of 0.5-3 um;
after the mechanical polishing is finished, a flatness image tester is adopted to measure the flatness of the glass substrate to be 7.1um and 6.1um.
Example 4
The photomask substrate raw material is a synthetic quartz glass substrate, the size of which is 800 multiplied by 960mm (the diagonal length is 1250 mm), the thickness of which is 9.8mm, and the processing method comprises the following steps:
step 1, performing primary treatment on a glass substrate;
horizontally placing the glass substrate on a rubber vacuum chuck of a carving machine, and performing edge grinding, edge grinding and chamfering processing;
s2, carrying out spray cleaning on the glass substrate;
the glass substrate is placed in a water tank, the front side and the back side of the glass substrate are cleaned in a spraying mode, and after the glass substrate is cleaned in the spraying mode, water marks on the front side and the back side of the glass substrate are dried through clean compressed air.
And step S3: obtaining measurement data for processing the glass substrate, and determining a processing scheme according to the measurement data;
the flatness image tester is used for measuring the flatness, parallelism, thickness and surface shape of the glass substrate, and the total feed amount of the rough grinding process is calculated.
The processing scheme comprises the following steps:
selecting a surface with poor flatness as a front surface, wherein the other surface is a back surface, and the front surface is a first processed surface;
grinding the glass substrate;
and polishing the glass substrate.
In this embodiment, the original glass substrate has a flatness a-plane of 250um, a b-plane of 993um, a parallelism of 67um, and a thickness of 10.044mm, and the a-plane having poor flatness is used as the front surface.
S4, processing the glass substrate according to the processing scheme;
keep flat the glass substrate on flat grinder's magnetism is inhaled table surface, uses the accurate clearance chi of 10um, 20um, 50um thickness, measures the clearance that closes on between raw and other materials glass substrate and the table surface, fills the adjustment clearance through the accurate clearance chi of suitable thickness.
The grinding process of the glass substrate includes: and selecting diamond grinding wheels with different grain diameters to carry out rough grinding, semi-fine grinding and fine grinding on the glass substrate in sequence, and spraying and cleaning the glass substrate after grinding each time.
The polishing process of the glass substrate includes: and performing rough polishing and fine polishing on the glass substrate in sequence.
Step S41, carrying out coarse grinding processing on the glass substrate;
carrying out rough grinding by using a diamond grinding wheel with the particle size of 270#, continuously feeding the diamond grinding wheel of 270#, after reciprocating motion in the Y-axis direction once, intermittently feeding the diamond grinding wheel of 270#, perpendicular to the front surface of the glass substrate, in the Z-axis direction once, wherein the single feeding amount is 10 microns, and the total feeding amount is 260 microns.
And turning the glass, grinding the surface A, continuously feeding the 270# diamond grinding wheel along the Y-axis direction at a speed of 400mm/min, and feeding the 270# diamond grinding wheel along the Z-axis direction by 10um in a single time, wherein the total feed is 110um. After the grinding procedure is finished, the surface of the glass substrate is washed clean by pure water and then dried by clean compressed air. And measuring the flatness of the surface of the ground glass substrate by adopting a VML7S ultra-precise electronic level meter, and measuring the flatness to be 13.7um.
Step S42: carrying out semi-finish grinding processing on the glass substrate;
carrying out semi-fine grinding by using a diamond grinding wheel with the particle size of 500#, continuously feeding the 500# diamond grinding wheel at the speed of 400mm/min along the Y-axis direction, after carrying out reciprocating motion once along the Y-axis direction, intermittently feeding the 500# diamond grinding wheel once along the Z-axis direction to be vertical to the front surface of the glass substrate, wherein the single feeding amount is 5 mu m, and the total feeding amount is 30 mu m.
And turning the glass, grinding the surface A, continuously feeding the 500# diamond grinding wheel at a speed of 400mm/min along the Y-axis direction, performing single feeding of the 500# diamond grinding wheel along the Z-axis direction by 5 micrometers, performing total feeding by 30 micrometers, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Step S43: carrying out fine grinding processing on the glass substrate;
carrying out fine grinding by using a diamond grinding wheel with the grain diameter of 800#, continuously feeding the diamond grinding wheel of 800#, after carrying out reciprocating motion once along the Y-axis direction, intermittently feeding the diamond grinding wheel of 800#, wherein the diamond grinding wheel is vertical to the front surface of the glass substrate along the Z-axis direction, the feeding amount of each time is 3um, and the total feeding amount is 10um.
And turning the glass, grinding the surface A, continuously feeding the 800# diamond grinding wheel along the Y-axis direction at the speed of 400mm/min, performing single feeding of the 800# diamond grinding wheel along the Z-axis direction by 3um, and performing total feeding of 10um, after the grinding process is finished, washing the surface of the glass substrate by pure water, drying the glass substrate by clean compressed air, and measuring the surface flatness of the ground glass substrate by a VML7S ultra-precise electronic level meter.
Carrying out fine grinding by using a diamond grinding wheel with the grain diameter of 1000#, continuously feeding the diamond grinding wheel of 1000# along the Y-axis direction at the speed of 400mm/min, after carrying out reciprocating motion once along the Y-axis direction, intermittently feeding the diamond grinding wheel of 1000# along the Z-axis direction to be vertical to the front surface of the glass substrate once, wherein the single feeding amount is 1um, and the total feeding amount is 5 um.
And turning the glass, grinding the surface A, continuously feeding the 1000# diamond grinding wheel at a speed of 400mm/min along the Y-axis direction, and continuously feeding the 1000# diamond grinding wheel at a single feeding amount of 1um and a total feeding amount of 5um along the Z-axis direction, wherein after the grinding process is finished, the surface of the glass substrate is washed clean by pure water and dried by clean compressed air, and the surface flatness of the ground glass substrate is measured by adopting a VML7S ultra-precise electronic level meter.
Step S44: roughly polishing the glass substrate;
the rough polishing comprises the following steps: after grinding, polishing the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 1-5 um;
step S45: carrying out fine polishing processing on the glass substrate;
the fine polishing comprises the following steps: after grinding, carrying out chemical mechanical polishing on the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the particle size of 0.5-3 um;
after the mechanical polishing is finished, the flatness image tester is adopted to measure the flatness of the glass substrate to be 12.0um and 8.9um.
The implementation of the invention has the advantages that: the invention discloses a processing method of a photomask substrate, wherein the photomask substrate is made of a glass substrate, and the processing method comprises the following steps: performing edge grinding, chamfering and spray cleaning on the glass substrate to obtain measurement data for processing the glass substrate, determining a processing scheme according to the measurement data, and sequentially performing grinding with different precisions by using diamond grinding wheels with different precisions; the method has the advantages that after grinding, the glass substrate is subjected to rough polishing and fine polishing in sequence by using polishing equipment, grinding with different accuracies is performed in sequence by using diamond grinding wheels with different accuracies, the flatness of raw materials is rapidly improved, meanwhile, a damage layer on the surface of the glass substrate after the last grinding is gradually removed, when the raw materials reciprocate along the X-axis direction, the diamond grinding wheels continuously feed along the Y-axis, the advancing track of the glass substrate is similar to a W shape, the uniform frosted surface without feed marks and steps can be obtained after grinding, the requirements on the raw materials are not high, the process flow is simple and convenient, the processing efficiency is high, the production cost is low, and the economic utility is high.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed herein should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A photomask substrate processing method is characterized in that the photomask substrate is made of a glass substrate, and the processing method comprises the following steps:
carrying out primary treatment on the glass substrate;
carrying out spray cleaning on the glass substrate;
obtaining measurement data for processing the glass substrate, and determining a processing scheme according to the measurement data;
the glass substrate is processed according to a processing recipe.
2. The method of claim 1, wherein the preliminary treatment of the glass substrate comprises: and (3) flatly placing the glass substrate on a rubber vacuum chuck of a carving machine, and performing edge grinding, edge grinding and chamfering processing.
3. The method of claim 1, wherein the spray cleaning of the glass substrate comprises: the glass substrate is placed in a water tank, the front side and the back side of the glass substrate are cleaned in a spraying mode, and after the glass substrate is cleaned in the spraying mode, water marks on the front side and the back side of the glass substrate are dried through clean compressed air.
4. The method according to claim 3, wherein the measuring the basic data of the glass substrate comprises: the flatness, parallelism, thickness and surface shape of the glass substrate were measured using a flatness image tester, and the total feed amount of the grinding process was calculated from the surface shape of the glass substrate.
5. The method according to claim 4, wherein the processing recipe comprises:
selecting a surface with poor flatness as a front surface, wherein the other surface is a back surface, and the front surface is a first processed surface;
grinding the glass substrate;
and polishing the glass substrate.
6. The method of claim 5, wherein the grinding the glass substrate comprises: the method comprises the steps of flatly placing a glass substrate on a magnetic suction working table surface of a surface grinding machine, using precision clearance rules with different thicknesses, measuring a proximity clearance between a raw material glass substrate and the working table surface, filling an adjusting clearance through the precision clearance rules with proper thickness, selecting diamond grinding wheels with different particle sizes to sequentially perform rough grinding, semi-fine grinding and fine grinding on the glass substrate, and spraying and cleaning the glass substrate after grinding each time.
7. The method for processing a photomask substrate according to claim 6, wherein the rough grinding method comprises: the method comprises the following steps of carrying out rough grinding by using a diamond grinding wheel with the particle size of 270#, enabling a glass substrate to reciprocate along the X-axis direction, enabling the diamond grinding wheel to feed continuously along the Y-axis direction, enabling the diamond grinding wheel to feed intermittently again along the Z-axis direction and perpendicular to the front surface of the glass substrate after the diamond grinding wheel reciprocates once along the Y-axis direction, carrying out rough grinding and spray cleaning on the back surface of the glass substrate after the front surface of the glass substrate is rough ground and spray cleaned, and measuring the surface flatness of the ground glass substrate.
8. The method of claim 6, wherein the semi-finish grinding comprises: and after the half fine grinding and spray cleaning of the front surface of the glass substrate, performing half fine grinding and spray cleaning on the back surface of the glass substrate, and measuring the surface flatness of the ground glass substrate.
9. The method of claim 6, wherein the finish grinding comprises: the method comprises the steps of carrying out fine grinding by using a diamond grinding wheel with the grain diameter of 800# -1340#, enabling a glass substrate to reciprocate along the X-axis direction, continuously feeding the diamond grinding wheel along the Y-axis direction, intermittently feeding the diamond grinding wheel along the Z-axis direction to be vertical to the front surface of the glass substrate once after the diamond grinding wheel reciprocates once along the Y-axis direction, carrying out fine grinding and spray cleaning on the back surface of the glass substrate after the front surface of the glass substrate is subjected to fine grinding and spray cleaning, and measuring the surface flatness of the ground glass substrate.
10. The photomask substrate processing method according to claim 5, wherein the polishing processing of the glass substrate comprises: carrying out rough polishing and fine polishing on the glass substrate in sequence; the rough polishing comprises the following steps: after grinding, polishing the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into a star disk, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 1-5 um; the fine polishing comprises the following steps: and after grinding, carrying out chemical mechanical polishing on the raw material glass substrate by using polishing equipment, flatly placing the glass substrate into the star plate, contacting the upper surface and the lower surface of the glass substrate with a rough polishing pad, and selecting polishing powder with the granularity of 0.5-3 um.
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